VOLUME 68 607

CrustaceanaV ol.68 (1995) pp. 1-11 NEBALIALAGARTENSIS (LEPTOSTRACA)ANEW SPECIESFROM THE YUCATAN PENINSULA, MEXICO ELVAESCOBAR-BRIONES Laboratoriode Ecolog õÂadelBentos, Instituto de Cienciasdel Mar y Limnolog õÂa, UniversidadNacional Aut onoma de Mexico, Apartado Postal 70-305, 04510 Mexico City, Mexico JOSEÂLUIS VILLALOBOS-HIRIART Colleccion Carcinol ogica, Instituto de Biolog õÂa,Universidad Nacional Aut onoma de Mexico, ApartadoPostal 70-153, 04510 Mexico City, Mexico Anewspecies of Nebalia isdescribed from R õÂaLagartosin the Y ucat an Peninsula, Mexico, increasing thenumber of described species in this genus to 13. The species closely resembles a complexof species recognizedfor the tropical western Atlantic that will need further study. The importance of the shape of thedenticles on the dorsal pleonal segments 6 and7 asa taxonomicalcharacter is discussed.

CrustaceanaV ol.68 (1995) pp. 12-20 RESTITUTION DE PSEUDORHOMBILA XANTHIFORMIS GARTH, 1940, POUR NANOPLAX GARTHI GUINOT,1969 (DECAPODA, GONEPLACIDAE) RESTORATION OF PSEUDORHOMBILA XANTHIFORMIS GARTH, 1940,FOR NANOPLAX GARTHI GUINOT,1969(DECAPODA, GONEPLACIDAE) MICHELE. HENDRICKX EstacionMazatlan UNAM, Apdo.Postal 811, Mazatlan, 82000 Sinaloa, Mexique Therecent collection of two females and one male of Pseudorhombilaxanthiformis Garth,1940, in theGulf ofCalifornia,permits to complete the de® nition of thisspecies previously known from female specimens only. P.xanthiformis wastransferred to the genus Nanoplax Guinot,1969, as N. garthi Guinot,1969, nom.nov. A closeexamination of the sternum-abdomen organization and of the sexual pleopods of the male,and the comparison of thisfresh material of P.xanthiformis , with P.quadridentata (Latreille,1828), P.octodentata Rathbun,1906, and P. guinotae Hernandez-Aguilera,1982 on the one hand, and on the otherhand with Nanoplaxxanthiformis (A.MilneEdwards, 1880), the type-species of Nanoplax, lead usto the conclusion that Garth’ sspeciesshould be maintained in the genus Pseudorhombila A. Milne Edwards.

CrustaceanaV ol.68 (1995) pp. 21-26 PARASITIC COPEPODS FROM ISURUS OXYRINCHUS RAFINESQUE, 1810, FROM THECENTRAL ATLANTICOC EAN JERZY ROKICKI and JOLANTA MOROZINSKA Departmentof Invertebrate Zoology, University of Gda nsk, Al. Piø sudskiego 46, 81-378 Gdynia, Poland Sixspecies of parasitic copepods were collected from 63 specimens of Isurusoxyrinchus ,takenin the CentralAtlantic. The occurrence of Pandarus¯ oridanus onthis shark constitutes a newhost record. Pandarus¯ oridanus wasfound in themouth and on the gills of its host. Previous records are apparently fromthe surface of the body.

CrustaceanaV ol.68 (1995) pp. 27-37 AGARUM KELPBEDS AS NURSERY HABITATOFSPOTPRAWNS, PANDALUS PLATYCEROS BRANDT,1851(DEC APODA, CARIDEA) JEFFREY B.MARLIAVE and MYRON ROTH VancouverAquarium, P .O.Box 3232, V ancouver,B.C., Canada V6B 3X8 Thespot prawn, Pandalusplatyceros Brandt,1851, predominantly uses kelp beds of Agarum sp.as nursery habitatin waters of southern British Columbia. Census data indicate interannual ¯ uctuationsin numbers ofshrimpsettling into nurseries. Analysis of sizesamples indicates settlement primarily in Mayand June, 608 VOLUME 68 withlesser rates of settlement through the summer. Growth of about 3 mm CL permonth can occur throughsummer and fall, with juveniles apparently emigrating from nurseries, starting in thefall, at sizes of16-20 mm CL. Juvenileswhich fail to reach such size before winter remain in the nursery habitat, withslower overall growth at about 1 mmCLpermonth. This difference in durationof residence in kelp bednursery habitat, together with different juvenile growth rates, leads to the conclusion that the age of spotprawns at a givensize will be variable. Due to this variable early life history and growth, length frequencymodes of spot prawns could include a mixedage group.

CrustaceanaV ol.68 (1995) pp. 38-42 REDESCRIPTION OF ALEBIONCARCHARIAE KRé YER, 1863 (COPEPODA, SIPHONOSTOMATOIDA) FROM ISURUS OXYRHINCHUS IN SOUTH AFRICA W.H.OLDEWAGE Departmentof Zoology, Rand Afrikaans University, P .O.Box524, Johannesburg, 2000, South Africa Two speciesof the genus Alebion havebeen recorded from sharks off the coast of southern Africa. The specimenswere not fully described. The present work describes Alebioncarchariae taken from Isurus oxyrhinchus takennear Cape Recife, South Africa. The new specimens bear some resemblance to the originaldescription of Alebioncarchariae and Alebioncrassus ,butdiffers from them signi® cantly in especiallythe morphology of the genital segment.

CrustaceanaV ol.68 (1995)pp. 43-60 NOUVELLES RECOL TESET NOUVELLES ESP ECESÁ DEMAJIDAE DEPROFONDEUR DU GENRE OXYPLEURODON MIERS, 1886 NEW FINDINGS AND NEW SPECIES OFDEEP-SEA MAJIDS OFTHE GENUS OXYPLEURODON MIERS, 1886 B.RICHERDE FORGES ORSTOM, BPA5,Noum ea Cedex, Nouvelle-Cal edonie Majidcrabs of the genus Oxypleurodon fromIndonesia, New Caledoniaand Wallis and Futuna Islands, are studiedhere and their morphological characteristics precised. The position of this recently rehabilitated genusin relation to the two most closely similar genera Sphenocarcinus A.MilneEdwards, 1878 and Rochinia A.MilneEdwards, 1875, can now be reexamined. Two newspecies are described, O. tavaresi sp.nov. from W allisIs., and O. karubar sp.nov. from the Moluccas.

CrustaceanaV ol.68 (1995) pp. 61-72 LIFEHISTORY OF GAMMARUSBALCANICUS SCHAFERNA,È 1922FROM THEBIESZCZADY MOUNTAINS (EASTERN CARPATHIANS, POLAND) DARIUSZ ZIELI NSKIÂ Dept.of Invertebrate Zoology and Hydrobiology, University of è odÂz,Â12/ 16Banacha St., 90-237 è odÂz,ÂPoland Lifehistory pattern of theamphipod Gammarusbalcanicus occurringin the W esternBieszczady Mountains isgivenand compared with literature data concerning the biology of this species.